SummaryDuring a 201/2‐month period, 115 surgical patients with intestinal diseases were evaluated for possible systemic infection. In 101 patients infection was suspected; antimicrobial therapy was administered promptly on the basis of a presumptive diagnosis after appropriate smears and cultures were obtained, but before the causal organisms were definitively identified or theirin‐vitrosusceptibility was determined. Of the 101 patients, serious infection was proved in 79; septicemia occurred in 25 per cent. Septic shock developed in 15 patients; only five died. The low mortality was attributed to prompt diagnosis and treatment. Further reduction in the incidence and mortality of septic shock may result from utilization of appropriate preventive measures.